Pope Francis has been sharply criticized for his lack of action on the Roman Catholic Church's sex abuse scandals. But some say his meeting with victims today – the first in his 16-month tenure – may mark a long-term, "zero tolerance" strategy in the making.

The pope has taken the Catholic world by storm since he was elected in March 2013, with a humanity that has seemed to transcend politics and divisive issues such as homosexuality and abortion. His mercy for the poor and ailing has touched Catholics and non-Catholics alike.

But when it comes to allegations of sex abuse at the hands of Roman Catholic priests, he's received constant flack. The Vatican has registered 3,420 accusations of abuse.

It’s taken almost a year and a half for him to meet with victims themselves, compared to his predecessor Pope Benedict, who was much less popular but met with victims on many trips around the world. This meeting – with victims from Ireland, Britain, and Germany – has also come under fire from victims’ groups in his native Argentina, who were excluded from this first encounter. And he raised a storm of criticism this year when he defended the church’s actions in general in the scandal. “The Catholic Church is maybe the only institution to have moved with transparency and responsibility,” Francis said. “No one else has done more. Yet the church is the only one to be attacked.”

This is the first time a pope has received victims inside the Vatican.

Despite the criticism, Marco Politi, a veteran Vatican observer in Rome and author of the new book “Francis Among the Wolves,” says he believes the pope is continuing the work of his predecessor and forging a new, structural response. He created a commission on sexual abuse, which includes women as well as a former victim, and has taken action to back up his stated goal of zero tolerance. Archbishop Jozef Wesolowski, a Polish bishop recalled from the Dominican Republic last September on claims of sexual abuse, was recently defrocked.

This meeting, Mr. Politi says, goes further than other papal gestures toward victims.

“If you meet a victim during a trip like other popes ... you have a mass, you listen quickly, and then you go ….,” says Politi. “This time he is inviting them to Rome, it is an upgrading of this gesture. It means that they are called to Rome to explain to the pope what has happened. He is ready to listen to their explanations.”

He asked for their mercy today during a mass that preceded his individual meetings with each victim. "I ask for the grace to weep, the grace for the church to weep and make reparation for her sons and daughters who betrayed their mission, who abused innocent persons," he said in his homily Monday. "I beg your forgiveness, too, for the sins of omission on the part of church leaders who did not respond adequately to reports of abuse."